A backhoe loader that is a work vehicle has a loader bucket at the front of the vehicle and a backhoe at the rear of the vehicle. Moreover, an operator seat provided in an operator cabin is configured in a rotatable manner to face toward the front when driving or operating the loader bucket, and face toward the rear when operating the backhoe.
A multi-shaft transmission is mounted in the backhoe loader described above. The transmission has an input shaft to which power from an engine is inputted, an output shaft that outputs power to the wheels, and one or more countershafts disposed between the input shaft and the output shaft. The shafts are provided with a hydraulic clutch for forward-reverse shifting, and a plurality of hydraulic clutches for speed shifting. Hydraulic clutch will be hereinbelow referred to simply as “clutch.”
Forward-reverse shifting clutches in a conventional transmission each have one forward clutch and one reverse clutch. However, in this configuration, the number of speeds when moving forward is limited and a multistage configuration cannot be achieved. As a result, acceleration performance during traveling is poor from a medium speed to a high speed.
Accordingly, increasing the number of speed shifting clutches to establish multistaging has been considered. However, when the number of speed shifting clutches is increased, the number of components increases and the overall transmission becomes larger. Moreover, when the number of speed shifting clutches is increased for forward movement, the number of stages for reverse movement which is unnecessary for multistaging is also increased in addition to the forward side.
To resolve this type of problem, a transmission disclosed in Japanese Patent Laid-open No. H11-230278 has been provided. The transmission disclosed in this publication is equipped with an input shaft, two countershafts, and an output shaft. A reverse clutch and a low-speed forward clutch are provided on the input shaft, and a high-speed forward clutch is provided on one of the countershafts. Moreover, three clutches are provided as speed shifting clutches.
As described above, since the transmission disclosed in Japanese Patent Laid-open No. H11-230278 has a forward low-speed clutch and a forward high-speed clutch as clutches for low-high speed shifting when moving forward, and has first to third clutches as speed shifting clutches, six forward speed stages can be achieved and multistaging can be realized with a few number of components.